Some Problems with Battery Drain

gizz

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Just picked up 4 cams that have been out for a week. All of them are at zero meaning all pics have been taken. All cams are Owl PF, MS20, 12V 1.2Amp batt's. 2 cams with timer and 2 without. The 2 with timers (one-shot) are completely dead (batt ran to very low voltage) and the two w/out timers are still working fine with good voltage. Could the draw from the timer and PIR be too much for the 12V batt to handle? I made sure each batt was fresh before I put them out. They were out a total of 1 week. I'm gonna put a fresh batt in one of them and put it in the closet. I'll check it each day and find out how long it's lasting. Seems kinda odd that I'm having a problem with the cams that have timers and not with the cams that don't. I'll let you in on the results once I know more. If this is gonna be a problem then I may be removing the timers.
 



gizz

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I did some checking and the batt's are down to between 5 & 6 volts. This timer is NOT the Welby/Tinhorn one-shot timer but rather a timer I got off of someone else a while back. I put a couple of these into some of my cams but had never left them more than 1 or 2 nights so I didn't know they would be a problem after a week or so in the woods. I'm not 100% sure it's a timer problem although I didn't have any problems with the others that didn't have the timer and the timer being the only part that is different. I'm gonna do some more testing on these this week and see if i can measure the current draw (Tinhorn taught me how :smile-blue )
 

spectr17

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Gizz,

That would be the next step, measure the current draw with a timer and without to see how much drain the timer has. If the timer is drawing a bunch more juice you could always go to a larger gel-cell battery.
 

bradleydale

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This brings up a question I was wanting to ask you guys..I am running 8 AA batteries to furnish my 12 volts. Do you guys know what this setup equals as far as amp hours?? This seems to be lasting good for me but I want to go to a gell cell of equal strength.
 
A

Archilochus2

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Hi gizz.......Are you using CMOS low-power "TLC" (somtimes "LM") 555's or the "NE" (sometimes "SA") bipolar timers??  The CMOS "TLC" versions shouldn't add much batt drain when used with the MS20 sensor - maybe ~ 10 to 15% increase in total power consumption if you have two 555's in the circuit.
If you are using the low-power "TLC" 555's, maybe the resistor values you have chosen or the capacitor types you're using are leading to excessive power drain.  Or maybe your timer circuits are energizing the shutter relays for a longer time than your non-timer cameras?
>>>>>>>>
bradleydale...... One long-life alkaline "AA" battery has an Amp-hour rating of ~2.8 (2800mAh) at a cell voltage of ~1.5V.  When you connect them in series, you raise the voltage but the Amp-hour capacity remains about the same - so you'll have 2800mAh @ 12V.
Remember that these Amp-hour ratings are calculated with the batteries being drained to a cell voltage of ~0.9V.  At near maximum discharge your circuit may not work properly, if at all.  So your might not get as much life out of the batts as the mAh rating would suggest.

Archilochus
 

gizz

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Arch - I'm using a circuit that was offered way back on the TNDEER site. It uses mainly transistors and a CAP to control the desired "one-shot" then off result. It does not use a TIMER chip of any type. This is really not a timer but rather a board that will hold the shutter closed for a period of about 3 to 4 seconds then "let-off" so that the camera does not go to sleep. Since it is not my idea i know very little about it but it other than it seemed to work when I tested it. It still does but seems to be eating batteries alot. I haven't tested the draw yet but I will this week. I was on vacation for a couple days and just got back this evening. I'll let you and the others know when i get some results.

(Edited by gizz at 7:58 pm on July 30, 2001)
 


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